This invention relates to the field of medical devices, and more particularly to a guidewire system for advancement through a highly occluded blood vessel.
Atherosclerosis resulting in a blockage of arteries can be a life threatening disease. Percutaneous intravascular procedures such as angioplasty and atherectomy were developed to open blocked vessels with as little trauma as possible. Angioplasty involves inflating a balloon positioned within the obstructive deposits or stenosis in the vessel, so that the stenosis is compressed against the arterial wall and the wall expanded to open up the passageway. Atherectomy involves selective excision and removal of obstructive deposits from the vessel walls.
An essential first step in these percutaneous procedures is maneuvering the distal operative extremity of the angioplasty or atherectomy catheter into position at a precise point inside the arterial occlusion. Maneuvering through small branched vessels and the stenosis itself can be very difficult and tedious. Especially difficult in this respect are chronic total occlusions (CTO). While most CTOs are not totally obstructed, only a small tortuous channel passes through the stenosis.
The guidance system used to position the catheters must be both effective and safe, because if they cannot be positioned precisely into place, the stenosis cannot be treated. Additionally, inadequate guidance carries a risk of perforation of the vessel that exceeds the benefits of recanalization.
The use of a guidewire is ideal in terms of effectiveness, safety, simplicity, and cost. Typically, a guiding catheter is inserted into the patient's aorta with its distal tip seated in the ostium of the desired coronary artery. The guidewire is then maneuvered into place while its progress is fluoroscopically monitored. Once the guidewire passes through the stenosis, the angioplasty or atherectomy catheters can be advanced over the guidewire and into place within the stenosis.
The distal end of the guidewire may be shaped, e.g. bent, at an angle up to 90.degree. from its longitudinal axis, so that torquing the proximal end of the guidewire from outside the patient can guide the distal tip of the guidewire into branch arteries. While it is known that vibrating a guidewire can help its passage through an occluded artery, such vibration has not been shown to be successful in highly occluded passageways such as CTO's.
What has been needed is a vibration device with the superior guidewire steerability and ease of use which results from having the guidewire free to rotate or move longitudinally relative to the distal tip of a guiding catheter even though the guidewire is attached to the vibrating mechanism. By providing for simultaneous manipulation of more than one variable of the guidewire, such a device gives the operator greater control over the guidewire position. Furthermore, such a device would have superior ease of use because unclasping, repositioning, and reclasping the guidewire to the vibration mechanism would not be required each time the guidewire needed to be rotated or moved relative to the guiding catheter.
Additional guidewire control would be provided by a guiding catheter with a bend in the distal tip which could be varied incrementally from 0.degree. to 90.degree. from its axis, while the catheter was inside a patient vessel. When attached to a vibrating device, a catheter with such in situ variability would allow the distal end of the guidewire to oscillate at a variety of angles to the longitudinal axis of the catheter, and would be useful in accessing off-center channels and side branches.
The vibration device of the present invention provides such a combination of desirable properties.